Olive Ridley Turtles: Conservation of Nesting Sites along the Coast of Odisha

By Rohan Nath

Introduction

The well-being of a seabeach decides the population of sea turtles residing on them. Sea turtles are highly dependent on land for the reproduction phase of their life. Even though predation of both hatchlings and adults by whales, sharks, large fishes and saltwater crocodiles, play a role in their mortality, the prime reason of turtle mortality is due to certain marine fishing practices. On the beach, predators like birds, beach mammals, insects and crabs’ prey upon both eggs and hatchlings. Hence, threats to beaches which are used as a nesting habitat to the sea turtles hampers the reproduction of sea turtles. Anthropological activities like sand mining, cluttered beaches, developmental activities along the coast and coastal armouring harms the habitat of these sea turtles.

According to WII-DGH Turtle Project Interim Report of 2011, there is a high affinity between sea turtles and their breeding grounds and hence, the whole population can suffer a serious damage due to reduction or loss of even a single rookery. The National Research Council reported in 1990 that urbanization and developmental activities on the coast have destroyed the nesting beaches of the Indian sea turtles.

Several researchers are currently involved in the conservation of the habitat of olive ridley sea turtles (Fig. 1) along the coast of Odisha and how developmental activities affect the sea turtles and their nesting habitats.

Fig. 1. Olive Ridley turtle hatchlings at Gahirmatha nesting ground in Odisha.
Image Source: India Times

Location

The state of Odisha has seven districts with coasts: Puri, Ganjam, Jagatsingpur, Khurda, Bhadrakh, Kendrapara and Balasore with a coastline of about 480km (Table 1) (Fig 2). Along the coast, there are around 250 coastal fishing villages.

Table 1. The coastal districts of Odisha and their characteristics.

Fig. 2. The coastal districts of Odisha.
Image Source: https://www.researchgate.net/figure/Coastal-districts-of-Orissa_fig2_226504527

Developmental activities along the coast of Odisha

The developmental activities along the coast of Odisha are summarised below (Table 2).

Table 2. Developmental activities

The destruction of nesting habitats of sea turtles due to developmental activities

The construction of ports requires the dumping of sand or silt to increase the level of the site of port construction. The biodiversity is affected by the supplementary construction in locations surrounding the port site resulting in an increase in pollution, land use changes, and the destruction of natural habitat. Olive ridley turtles generally breed in the offshore waters of Odisha. The entire food chain of the sea turtles is affected due to the vast amount of dredging of shipping channels which have an effect on the light penetration and turbidity of the water on the benthic habitats. This can result in an increase of biochemical oxygen demand and primary productivity of the water. Intense amount of noise may discourage the adult olive ridley sea turtles from foraging sites and nesting grounds.

Ports, specifically Indian ports in depraved conditions are responsible for water pollutions from cargo discharges, accidental fuel oil leaks and bilge cleaning. Large mega-ports have an adverse effect on the biodiversity of the coast. The breeding sites of the turtles have been degraded by elevated noise levels and pollution. Light pollution hampers the survival of the hatchlings and the nesting behaviour.

The vast number of fish landing centres and fishing harbours and jetties pose a serious threat to the population of the sea turtles. The construction of new fishing harbours and jetties by the Government of Odisha may further aggravate the issue. New fishing harbours might lead to more intense fishing activities and mechanized fishing fleets increasing the accidental catch of turtles.

Casuarina plantations lead to a reduction of nesting space and harms the nesting behaviour of the turtles. It changes the topography of the beach by deposition of litter and its root growth limiting the space available for the turtle to nest. Predators like jackals and hyenas which predates on sea turtle eggs takes cover in these plantations.

Numerous defence facilities and establishments affect the nesting sites of the sea turtles. The training centre INS-Chilika and Golabandha, the missile test programme at Chandipur-on-sea and Wheeler Islands are positioned close to the nesting sites and the target ranges are in the offshore open waters where the turtles aggregate for breeding. Critical behaviours of the sea turtles like, nocturnal sea-finding behaviour and nest site choice of both hatchlings and nesting females are disrupted due to artificial illumination of these establishments.

Reference

  1. Behera, S., & Tripathy, B. (2014). Review of current developmental activities and their possible impact on olive ridley sea turtles along the Odisha Coast of India. Testudo, 8(1), 38-55.

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